The 250 R-ES Trail Boss, produced between 1985 and 1995, represents a robust and versatile all-terrain vehicle designed for off-road exploration and utility. Known for its reliable engineering and adaptability, the Trail Boss line has been a significant offering from a respected American powersports manufacturer. This particular model, often featuring a 250cc two-stroke engine and an automatic transmission, was built to handle diverse terrains, offering a blend of power and maneuverability that made it a competitive choice in its segment. Its design prioritizes durability and ease of operation for recreational and practical use in various outdoor environments. This comprehensive workshop service manual provides essential guidance for the maintenance, repair, and troubleshooting of the 250 R-ES Trail Boss from 1985 through 1995. It covers all major systems, including the engine, transmission, fuel, ignition, electrical, exhaust, bodywork, frame, and chassis. The manual details routine maintenance procedures, diagnostic steps, repair and overhaul instructions, assembly and disassembly processes, and tune-up procedures. Furthermore, it includes critical technical specifications, wiring diagrams, torque values, and information on specialized tools, ensuring that technicians and owners have the most accurate and reliable information for effective vehicle upkeep and repair.